title: Early increase of CD4+ CD45RA+ and CD4+ CD95- cells with conserved repertoire induced by anti-retroviral therapy in HIV-infected patients.
abstract: Administration of anti-retroviral drugs induces a decrease of viral load associated with increase of CD4+ cell count in most HIV-infected patients. To investigate the early changes in CD4+ cell phenotype induced by anti-retroviral therapy, six patients with CD4+ cell count > 100/mm3 and never treated with anti-HIV therapy were enrolled and blood samples collected several times within 14 days from the initiation of therapy with Zidovudine plus Didanosine. CD4+ cell count and HIV viraemia were investigated at each time point, as well as the expression of CD45RA, CD45RO and CD95/Fas molecules on CD4+ cells, and the T cell receptor (TCR) Vbeta repertoire of CD4+ cells. All patients showed a rapid and dramatic decrease in viral load with a corresponding increase of CD4+ cell count. The main remodelling of CD4+ cell subpopulations took place in the first 14 days of therapy, and consisted of: (i) increased CD4+CD45RA+/CD4+CD45RO+ ratio; (ii) decrease of CD95/Fas expression. The rise in absolute number of CD4+CD45RA+ cells was paralleled by an increase of CD4+CD95/Fas- cells and accounted for most of the early increment of CD4+ cell count. The TCR Vbeta repertoire of CD4+ cells was conserved after anti-HIV therapy, with the exception of two patients with expanded CD4+Vbeta12+ cells, which also tested CD45RA+ and CD95/Fas-. These experiments show that newcomer CD4+ lymphocytes are CD45RA+CD95/Fas- cells, suggesting that blocking HIV replication causes an early and antigen-independent proliferation of possibly 'naive' cells unprimed for CD95/Fas-mediated apoptosis. These cells expressed a conserved and widespread TCR repertoire, suggesting that their capability for antigenic recognition is intact.
authors.affiliation: Department of Internal Medicine, University of Ancona Medical School, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Silvestri
authors.forename: C
authors.initials: C
authors.lastname: Munoz-Calleja
authors.forename: P
authors.initials: P
authors.lastname: Bagnarelli
authors.forename: G
authors.initials: G
authors.lastname: Piedimonte
authors.forename: M
authors.initials: M
authors.lastname: Clementi
authors.forename: M
authors.initials: M
authors.lastname: Montroni
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000276:immunology* / Q000627:therapeutic use; D017951:Antigen Presentation; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D015658:HIV Infections / Q000188:drug therapy / Q000276:immunology*; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D016130:Immunophenotyping; D017493:Leukocyte Common Antigens / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects*; D008297:Male; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000276:immunology; D019014:fas Receptor / Q000276:immunology
chemical_list: D019380:Anti-HIV Agents; D016693:Receptors, Antigen, T-Cell, alpha-beta; D019014:fas Receptor; D017493:Leukocyte Common Antigens